A disk drive is a common data storage device. For example, in magnetic-medium-based storage devices, data is typically stored on circular, concentric tracks on a magnetic disk surface. A read-write head retrieves and records data on the magnetic layer of a rotating disk. When retrieving data, magnetic field variations are converted into an analog signal that is amplified and converted to a digital signal for interpretation. Servo information may be embedded on the recording surface to guide a servo control in accurately positioning the head for read/write purposes. For example, the servo information may define the position of the data tracks.
Traditionally, a servo writer machine is used to write the embedded servo information on the disk surface. Present servo writers are typically large and expensive, and as the typical track density increases, the servo writing time also increases, which can create a constraint in the disk drive manufacturing process at the servo writer station. Self-servo write (SSW) systems are emerging to perform functions of the servo writer machines. SSW systems include hard disk drives that are configured to write the servo information for timing and/or positioning in-situ. Such SSW systems may reduce costs associated with external servo writers.
A timing transient may occur while the SSW system is writing embedded servo information on the disk surface, which may result in a jump in decoded position or a gap or squeeze in the embedded servo information. Techniques and supporting configurations are needed to detect and recover timing slips in SSW systems to provide accurate embedded servo information for reading and writing data on the disk.